Introduction:
Many of our log /timber home design customers plan to build on a remote property away from power lines.
Living without power is not an option as we are so used to the comforts electricity brings us.
Building power lines to the property can easily cost many $10 000.
And even if you have power at the end of a long line, chances are you will be out for days during a winter storm.
No light in the house, no computer, TV or radio working, no water running and may be no heat, makes it an unforgettable experience.
Start the car and rush back to the city becomes the only option…
UNLESS you create your own on site power.
Glossary:
Direct current (DC) has a unidirectional flow and is produced by batteries, solar cells.. with voltages at 12, 24 or 48 volts being most common.
Alternative current (AC) periodically reverses direction.
Most house appliances use AC. Voltage is higher than DC to allow transmitting along great distances with little loss.
Amperage (A) is the amount of electrical flow passing through a wire.
Voltage (V) is the force, tension or “pressure” with which electricity moves down a wire.
Wattage (P) is the electrical power generated from an amount of electric flow multiplied by the pressure or tension applied to that flow.
Power (W)= amperage (A) x Voltage (V)
1000 watts = 1 KiloWatt (kW)
Energy (Wh)= Power (Watts) x Time (Hour)
1000 Wh = 1 KiloWatt Hour (kWh)
1- Generators
Fossil fuel generators do create power in emergency situation.
Installation cost is very low.
However it is so expensive, inefficient, noisy and likely polluting to run, it is not a long term primary solution by itself.
A generator should be the last back up solution to your energy needs (when all renewable energy sources have failed), to charge the battery bank.
Most likely generator fuel available for remote site would be gasoline, diesel and propane.
A- Gasoline generator is most common portable unit for small power demand. However gasoline is inefficient, expensive and dangerous with a short shelf life under one year.
B- Diesel is much safer to use with a 2 year shelf life without additives.
It can be delivered but you need to install a storage tank for long use.
Liquid cooled engine life is highest at up to 20 000 hours.
It is best for medium to large operation.
It is however noisy, smelly and polluting.
Diesel is the best option for principal power and long term generator use.
C- Propane generator is a popular backup solution for off grid site, if a propane tank is already part of the energy system with home delivery available at site.
Operating noise level is low and propane is clean burning with a very long shell life.
However engine life span is as low as 500 hours for low cost budget minded air cooled engine and over 5000 hours for more expensive water cooled engines.
Fuel cost is usually high (unless delivered) coupled with higher installation and repair cost.
2- Renewable energy systems for an off grid site.
Water, sun and wind may be available on site to generate the renewable electrical power you need.
A- Micro-hydro renewable energy is by far the most reliable and cheapest energy source to invest in.
If your property has a year round running stream with at least 20′ drop (static head) and minimum 24 (GPM) gallon per minute flow of water, you have free power ready to be tapped for your personal use requiring a small investment.
Example:
1 PSI (pressure) is equal to 2.31 feet of head.
So a 20 foot head will produce 8.65 PSI minus pipe friction.
Net head is equal to static head minus the friction head
Lets say we have a 17 foot net head after subtracting the friction head.
And lets say we are working with a minimum of 24 GPM water flow.
An AC micro-hydro power (Watts) for such a minimum situation would be = net head x flow / 9 = 45 watts which is over 1KWH a day (already enough to run lights, laptops and a DC water pump).
Diameter size of pipe will limit the flow of water to the turbine.
The bigger diameter pipe, the bigger the flow, the higher the investment in the pipe.
Water flows the same, day and night so battery bank needs is much smaller or not necessary to store electrical energy compared to wind and solar power.
Thus investment to set up a micro-hydro system may be less than 10% of investment to set up wind or solar system for equivalent power generation level.
If the stream is seasonal, then a solar or wind hybrid system may be a solution.
B- Photovoltaic renewable energy is created by solar panels absorbing sunlight.
This is a simple system with no moving parts that requires battery banks to store the electrical energy, an inverter to convert DC battery power to AC power needed to run most appliances.
Inverters can get quite sophisticated and control an automated operation of the system.
Finding the best sunny unshaded location on your property is crucial to optimize the insolation of the panels from 10 am to 3pm when sun is highest in the sky. For maximum production output, panels should be angled for seasonal variation of sun position in the sky.
Panel roof mount is best to avoid theft or vandalism. Just make sure you can get to them to clean and adjust.
Ground level mount is fine if you can avoid vegetation shading.
Easy to install, adjust and clean.
Pole mounts are great and allow choosing any location for best result.
Sun tracking mount will somewhat increase the energy collected but moving parts will require maintenance.
The size of the solar panel array you need to install depends on the amount of sunlight at your site and how much power you need each day to run your household. If your energy need grows, it is easy to add more panels and more batteries.
C- Wind renewable energy is a great supplement to photovoltaic
energy as seasonal variations are usually complementary.
Few locations have constant prevailing wind above 10 mile per h or 16 km per h to use as a primary source of power.
Locations like the prairies, flat land and high areas or western exposed shore of a large lake are most suited for wind power production.
Most common horizontal axis wind turbines are installed at top of properly designed tower at least 40′ above trees and buildings to use non turbulent wind. Air turbulence is the main reason for wind generator break down.
Before investing lots of money in a wind generator and tower, use an anemometer to collect wind speed data for at least one year.
Or ask wind data from local meteorological station or airport.
Or simply observe if vegetation is permanently bent to one direction.
Install a flagpole and collect daily data on flag direction and stiffness.
Or if you like kites, this is time to fly it to predict best height for clean wind.
Wind generators produce AC current that needs to be rectified to DC to store in batteries. As wind is by nature a variable resource, large banks of batteries are needed to store the energy for calm weather periods.
About wind power, location is everything!
3- Size a renewable energy system to your power consumption.
The investment to install a renewable energy system for your off grid dwelling can be quite prohibitive.
Running heaters, dryers, stoves and hot water tanks on electricity does not make sense as you will need to buy numerous extra solar panels, bigger and higher wind turbines and ever larger banks of batteries to store the DC backup power.
Instead of spending big bucks installing a major on site power system, think conservation first, because the investment to generate our own power becomes financially unjustifiable when our wild needs for electric power is uncontrolled.
A- Conservation
Reducing your house electrical energy needs should become an obsession for the off grid dweller.
A dollar spent on increased efficiency will save you four dollars of investment on electricity generation.
An average home uses at least 1000 kWh per month.
A highly efficient home could use less than 200 kwh per month.
Lets look at what can be done…
– First, make sure your home is super insulated with minimum R20 in walls, R28 in floors over crawl space, and R50 in roofs.
– To heat your off grid home, use a wood or gas burning masonry stove (newsletter 13) with extra propane gas stoves/fireplaces for far away rooms.
– If you can get a propane tank on your remote site and propane delivery, then your cooking stove, and probably refrigerator should be running on propane.
-(Refrigerator and freezer use 3kWh per day)
– Select energy star appliances for your dish and clothes washer. Both washers should only be run full for maximum efficiency.
– Try to use a clothe line instead of a dryer. Clothes will last longer and smell so fresh…
– Hot water can be supplied by a solar water heater on the roof that collects the infrared from the sun, coupled with a propane run tankless water heater on demand as I discuss in newsletter 15.
– Add a grey water heat recovery system to preheat the water coming from outside water supply.
– Replace all incandescent bulbs with compact fluorescent that use 2/3 less energy for same amount of light.
– Save even more energy and use LED (light emitting diodes) instead of compact fluorescent which contains mercury.
– Use those LED as task lights under kitchen upper cabinets instead of flooding the room with bright lights.
– Use occupancy sensors to ensure lights are on only when in the room.
– Reduce stand by or phantom power loss.
Those electronic appliances we are so fond off, still consume electricity when we do not use them. Televisions, computers, printers, clocks and remote controls leak power day and night whether or not they are in use.
Power supplies that convert AC from wall socket to DC or low voltage AC for all our electronics lose 30% of energy in heat loss.
Connect all those wonderful toys to power bars that can be switched off instead of directly to a wall socket.
An average home continuously leaks at least 50 watts in stand by power or about 440 kWh per year.
This may be barely noticeable on our electricity bill back in the city.
However this power loss means more significant investment in alternative renewable energy system for the off grid site.
Last word…
At our lake cabin at the end of a 50 km power line that shuts down regularly for any wind storm, I have taken steps to be as independent as possible from our power utility supplier by changing stove, fridge and hot water heater to propane that is delivered to our property.
Our heat is produced by a wood burning masonry stove that is also able to cook our food.
I opted for a small back up propane generator to run our lights, computers and a few small appliances when power is off.
Next I will install a solar hot water heater on the roof to improve energy efficiency.
I changed most of the lights to LED.
All electronics are connected to power bars that allows us to really turn them off.
My goal is to set up a few solar panels on the roof with corresponding battery banks to take care of our basic electrical needs and hopefully say goodbye to our utility company…
